Adds additional index types

```
gs.addIndex({
  property: "date",
  index: dateIndex
});

gs.addIndex({
  property: "crime",
  index: btreeIndex
});

gs.within(
  geojson,
  {
    "date": {
      "between": [ "2013-01-01", "2013-02-01" ]
    },
    "crime":
    {
      "equals": "arson"
    }
  },
  function (err, data) { }
);
```

Adds to `contain` and `within` - tests are there.

I updated the GeoStore docs to reflect the removed deferreds.

We will want to revisit documentation in full, and have a better comprehensive documentation system.